Wind turbines are known to be erected onshore or offshore. In the case of an onshore wind turbine a foundation is built on the ground and the wind turbine is installed on the foundation. In the case of an offshore wind turbine, a foundation is connected to the seabed. It is also known to use a floating foundation that is supported by the water.
Wind turbines comprise a rotor, a nacelle, and a tower. The rotor comprises rotor blades and is rotatably connected to the nacelle. The nacelle is connected to the top of the tower. The tower of the wind turbine is connected to the foundation. The foundation comprises steel and/or concrete. The foundation transfers and distributes the weight of the wind turbine and the loads acting on the wind turbine to the medium on which the foundation is resting. In the case of an offshore foundation a gravity foundation, a monopole, a tripod or a jacket structure can be used.
An electric connection can be provided to the wind turbine to connect the wind turbine to an especially land based infrastructure. The wind turbine comprises an electrical system to deliver electrical energy to the connection. To achieve this, the wind turbine can for example comprise a transformer and/or a converter. The wind turbine can also comprise switchgear. Switchgear can be any combination of electrical disconnect switches, fuses and/or circuit breakers used to control, protect and isolate electrical equipment.
Within the last years, the electrical output power of wind turbines and their mechanical size have increased. Therefore the weight of the wind turbines and the loads acting on the wind turbines also increased. Therefore it is necessary to build heavier and stronger foundations.
Due to the higher output of electrical power, the electrical equipment in the wind turbine also tends to increase in size and weight, adding additional weight and loads to the wind turbine and the foundation. It is also advantageous to use a very rigid tower for the wind turbine, which results in a high weight and the use of a lot of material.
For the reasons mentioned above, increasing amounts of material are needed for these wind turbines and they are therefore more expensive.